1. Field of the Invention
The present invention relates to methods and apparatus for a laser and thermal imaging device. The invention also includes a method for enhanced scanning mirror control.
2. Description of Related Art
German Patent Application No. P 32 09201.1 describes how narrow band, 10.6 .mu.m CO.sub.2 radiation bypasses the scanning element of a combined laser and thermal imaging device. CO.sub.2 radiation is focused by a detector objective on one of at least two detector elements of the thermal imaging device. The result is that the CO.sub.2 radiation, although it is received by means of the thermal imaging detector, it is not directed by the scanning mirror which is constantly changing its position. The advantage provided by the present invention that the angular movement of the mirror during the range measuring sequence need not be accounted for. As a consequence, when the laser pulse is triggered, a certain time interval (equal to the product of the mean range and twice the speed of light) would come into the range measuring operation. During this interval, the detector element of the thermal imaging device would have scanned a field of view of greater than the instantaneous detector field of view. This, in turn, means that false targets lying within this scanned field of view would be seen and measured, which would increase the false alarm rate, deteriorate the range resolution, and impair the system performance data.